WASHINGTON (MarketWatch) - Monthly capital flows to the United States reversed in December to the first outflow in a year-and-a-half, the Treasury Department reported Thursday. Monthly capital flows reversed to an outflow of $11 billion in December compared to an inflow of $70.5 billion in November. In December, private investors sold $42.5 billion of securities. This was offset by $31.5 billion in purchases by official institutions. Net long-term capital inflows, meanwhile, fell to $15.6 billion in December from $84.9 billion in November. This is the lowest inflow since January 2002. End of Story